Mike Mentzer was born on November 15, 1951 in Ephrata, Pennsylvania and grew up there. In grammar school and Ephrata High School, he received "all A's, though mostly A's and B's." He credits his 12th grade teacher, Elizabeth Schaub, for his love "of language, thought, and writing." In 1975, he started attending the University of Maryland as a pre-med student where his hours away from the gym were spent in the study of "genetics, physical chemistry, and organic chemistry." After three years he left the university. He said his ultimate goal during that period was to become a psychiatrist.[1][5]

Mentzer started bodybuilding when he was 12 years of age at a body weight of 95 lb (43 kg) after seeing the men on the covers of several muscle magazines. His father had bought him set of weights and an instruction booklet. The booklet suggested that he train no more than three days a week, so Mike did just that. By age 15, his body weight had reached 165 lb (75 kg), at which point Mike could bench press 370 lb (170 kg). Mike's goal at the time was to look like his bodybuilding hero, Bill Pearl. After graduating high school, Mentzer served four years in the United States Air Force. It was during this time he started working out over three hours a day, six days a week.[1]

Mentzer started competing in local physique contests when he was 18 years old and attended his first contest in 1969. In 1971, Mentzer entered and won the Mr. Lancaster contest. In 1971 he suffered his worst defeat, placing 10th at the AAU Mr. America, which was won by Casey Viator. Mentzer considered his presence at this contest important later on, as here that he met Viator who gave Mentzer the contact information for his trainer Arthur Jones. Due to a severe shoulder injury, he was forced to quit training from 1971 to 1974. In early 1975, however, he resumed training and returned to competition in 1975 at the Mr. America contest, placing third behind Robby Robinson and Roger Callard. Mentzer went on to win that competition the next year, in 1976. He won the 1977 North America championships in Vancouver, British Columbia, Canada, and competed a week later at the 1977 Mr. Universe in Nîmes, France, placing second to Kal Szkalak. In 1978, Mentzer won the Mr. Universe in Acapulco, Mexico with the first and only perfect 300 score. He became a professional bodybuilder after that 1978 Universe win.[1][2]

He retired from competitive bodybuilding after that show at the age of 29. He maintained that the contest was rigged until the day he died. While he never said he thought that he should have won, he maintained that Arnold should not have, though he eventually got on good terms with Schwarzenegger.[6][1]

Mentzer was an Objectivist and insisted that philosophy and bodybuilding are one and the same. He said "Man, is an indivisible entity, an integrated unit of mind and body." Thus, his books contain as much philosophy as they do bodybuilding information.[1]

Mentzer took the bodybuilding concepts developed by Arthur Jones and attempted to perfect them. Through years of study, observation, knowledge of stress physiology, the most up-to-date scientific information available, and careful use of his reasoning abilities, Mentzer devised and successfully implemented his own theory of bodybuilding. Mentzer's theories are intended to help a drug-free person achieve his or her full genetic potential within the shortest amount of time.[7]

High-Intensity Training the Mike Mentzer Way was Mentzer's final work. In it, he detailed the principles of high intensity weight training. Weight training, he insisted, had to be brief, infrequent, and intense, to attain the best results in the shortest amount of time. Heavy Duty II also espouses critical thinking. In this book, Mentzer shows why people need to use their reasoning ability to live happy, mature, adult lives, and he shows readers how to go about doing so. Bodybuilding was endorsed as only one potential component of an individual's existence, encouraging many other worthwhile pursuits throughout his books.[8]

Diet has always been as important, if not more, as weight-training for bodybuilders. However, in his book Heavy Duty Nutrition, Mentzer demonstrated that nutrition for athletes did not need to be nearly as extreme as the bodybuilding industry would lead one to believe. His recommended diets were well balanced, and he espoused eating from all four food groups, totaling four servings each of high-quality grains and fruits, and two each of dairy and protein daily, all year-round.[9]

Mentzer believed that carbohydrates should make up the bulk of the caloric intake, 50–60%, rather than protein as others preferred. Mentzer's reasoning was simple: to build 10 pounds of muscle in a year, a total of 6000 extra calories needed to be ingested throughout the year, because one pound of muscle contains 600 calories. That averages 16 extra calories per day, and only four of them needed to be from protein—because muscle is 22% protein, about one quarter.[9]

While Mike Mentzer served in the US Air Force, he worked 12-hour shifts, and then followed that up with 'marathon workouts' as was the accepted standard in those days. In his first bodybuilding contest, he met the winner, Casey Viator. Mentzer learned that Viator trained in very high intensity (heavy weights for as many repetitions as possible, to total muscle fatigue), for very brief (20–45 minutes per session) and infrequent training sessions. Mentzer also learned that Viator almost exclusively worked out with the relatively new Nautilus machines, created and marketed by Arthur Jones in DeLand, Florida. Mentzer and Jones soon met and became friends.[10]

Jones pioneered the principles of high-intensity training in the late 1960s. He emphasized the need to maintain perfectly strict form, move the weights in a slow and controlled manner, work the muscles to complete failure (positive and negative), and avoid overtraining. Casey Viator saw fantastic results training under the direction of Jones, and Mentzer became very interested in this training philosophy.[10] Eventually, however, Mentzer concluded that even Jones was not completely applying his own principles, so Mentzer began investigating a more full application of them. He began training clients in a near-experimental manner, evaluating the perfect number of repetitions, exercises, and days of rest to achieve maximum benefits.[7]

For more than ten years, Mentzer's Heavy Duty program involved 7–9 sets per workout on a three-day-per-week schedule.[7] With the advent of "modern bodybuilding" (where bodybuilders became more massive than ever before) by the early 1990s, he ultimately modified that routine until there were fewer working sets and more days of rest. His first breakthrough became known as the 'Ideal (Principled) Routine', which was a fantastic step in minimal training. Outlined in High-Intensity Training the Mike Mentzer Way, fewer than five working sets were performed each session, and rest was emphasized, calling for 4–7 days of recovery before the next workout.[8] According to Mentzer, biologists and physiologists since the nineteenth century have known that hypertrophy is directly related to intensity, not duration, of effort (Mentzer 2003;39). Most bodybuilding and weightlifting authorities do not take into account the severe nature of the stress imposed by heavy, strenuous resistance exercise carried to the point of positive muscular failure.[7]

Mentzer's training courses (books and audio tapes), sold through bodybuilding magazines, were extremely popular, beginning after Mentzer won the 1978 IFBB Mr. Universe contest. This contest gathered a lot of attention, because at it he became the first bodybuilder ever to receive a perfect 300 score from the judges. Some time later, Mentzer attracted more attention when he introduced Dorian Yates to high-intensity training, and put him through his first series of workouts in the early '90s.[7] Yates went on to win the Mr. Olympia six consecutive times, from 1992–1997.

While in school, Mentzer's father motivated his academic performance by providing him with various kinds of inducements, from a baseball glove to hard cash. Years later, Mike said that his father "unwittingly ... was inculcating in me an appreciation of capitalism."[1]

According to David M. Sears, a friend of Mentzer and an editor and publisher of his Muscles in Minutes book, he stated that:[1]

As you know, Mike was a voracious reader of philosophy in college-so that would put him at, say 18 years old, in 1970. He read the more traditional philosophers then, and "probably" didn't fully embrace Ayn Rand until the mid-or later-1980's (since none of his writings mentioned her until at least the mid-80's if not later). In my opinion, Mike's ideas on bodybuilding were "allowed" to emerge because of his Objectivism. His approach to critical thought, analytical thinking, and knowing there is one truth, all allowed him to buck conventional thought and push onward with his own mental effort.

Regarding what he learned from Ayn Rand, Mentzer said in an interview:[1]

Learning logic and acquiring the ability to think critically is not easy, though not impossibly difficult. I learned how to do these things by reading and "digesting" the works of novelist/philosopher, Ayn Rand. To get started on the proper, methodical path read her books of explicit philosophic essays "Philosophy: Who Needs, It?"- especially the Introduction and the first two chapters-and "The Romantic Manifesto"-especially the second chapter, Philosophy and Sense of Life. After reading and re-reading the first couple of chapters from each of those books, put them aside for a while and read her two epochally great novels--"The Fountainhead" and "Atlas Shrugged," in that respective order. Just as is true with any other context of knowledge, philosophy must be studied in a logically structured order...

In his last interview before his death, Mentzer said he was delighted to get so many phone clients and close personal bodybuilding friends, such as Markus Reinhardt, who had been influenced by him to become Objectivists. He described Objectivism as the best philosophy ever devised. He also criticized the philosophy of Immanuel Kant, which he described as an "evil philosophy," because according to him Kant set out to destroy man's mind by undercutting his confidence in reason. He also criticized the teaching of Kantianism in schools and universities and said it's very difficult for an Objectivist philosopher with a Ph.D. to get a job in any of the universities.[12]

In the late 80s, Mentzer returned to training bodybuilders and writing for Iron Man magazine and spent much of the 1990s regaining his stature in the bodybuilding industry. Mike had met Dorian Yates in the 1980s and made an impression on Dorian's bodybuilding career. Years later when Yates won Joe Weider's "Mr. Olympia", he credited Mike's "Heavy Duty" principles for his training. Mike, his brother Ray, and Dorian formed a clothing company called "MYM" for Mentzer Yates Mentzer, also known as "Heavy Duty Inc", in 1994. MYM was based on the success of Don Smith's "CrazeeWear" bodybuilding apparel. The three principals wanted to capitalize on the physically fit lifestyle, which today has gone mainstream. With the blessing and promotion of Joe Weider, the trio manufactured and distributed their own line of cut-and-sew sportswear.[1]

Mentzer died on June 10, 2001 in Rolling Hills, California. He was found dead in his apartment, due to heart complications, by his younger brother and fellow bodybuilder Ray Mentzer. Two days later, his brother Ray also died in his sleep after complications from his long battle with Berger's disease.[3]

^INSIDE MIKE MENTZER by Dave Sears "Stopping at Mike's favorite Santa Monica coffee shop, we attracted attention to ourselves for both the automobile and our spirited debate about religion (Mike was an atheist, I am Catholic)."